Chapter 7: Adaptations to Environment Flashcards
Large diversity of species and of adaptations to ?
different environmental conditions
All species must acquire what to be fit?
- energy and matter to survive, grow and reproduce (to be fit)
AMWR for fitness?
- Acquisition and digestion of food (organisms put a lot of energy into acquiring and digesting food)
- Maintenance of body temperature
- Water balance
- Response to cycles of light and temperature
- 1 Size as a constraint on Evolution:
- Organisms range in?
size
- 1 Size as a constraint on Evolution:
- morphological and physiological features ____ with body size.
chane
- 1 Size as a constraint on Evolution:
- Surface area to volume ratio?
- smaller organisms have larger surface area relative to volume….
L> ratio = how much area is exposed to the environment vs volume of their body
Surface Area to Volume Ratio:
- Transfer needed between ___ and ____.
-environment and interior of organism Ex: oxygen
Surface Area to Volume Ratio:
- Diffusion is effective for what sized animals?
- small
Surface Area to Volume Ratio:
- Large organisms how do they get oxygen to their interior?
- active transport via lungs, circulatory system
Surface Area to Volume Ratio:
- Body size constraints also apply to other?
metabolic processes
Acquisition and Digestion of Food:
- variety of methods to acquire and digest foods such as?
- herbivory
- carnivory
- omnivory
Acquisition and Digestion of Food:
- each feeding group has characteristic adaptations. Such as?
ex: ruminants(mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through bacterial actions. ) like deer and cows are adapted to digest cellulose
* *omnivores do not digest cellulose well
Nutrition and Oxygen:
- need ____ and ___.
- mineral elements and amino acids
Nutrition and Oxygen:
- Release of energy from food mostly through____.
- aerobic respiration
Nutrition and Oxygen:
- need???
oxygen
Why is this more of a problem for aquatic organisms?
it goes via passive transport
- if the current was in the same direction you wouldn’t acquire as much oxygen
- *counter current
Regulation of Internal Conditions:
- Organisms must regulate their internal environment despite what?
- changes n the external environment aka HOMEOSTASIS
Regulation of Internal Conditions:
- Homeostasis?
the property of a system in which variables are regulated so that internal conditions remain stable and relatively constant.
Regulation of Internal Conditions:
-Regulated an internal system by homeostasis involves a ?
negative feedback …= the means to which a system returns back to a set point within the system
Regulation of Internal Conditions:
-Homeostatic plateau?
- max and min range (middle is where we want to be)
Regulation of Internal Conditions:
- organisms have a defined range for where they can?
function at
Regulation of Internal Conditions:
- Control of homeostasis is both ___ and ____
physiological and behavioural
Regulation of Internal Conditions:
- homeostasis is effective over a certain range of? (ex)
temperature
Regulation of Internal Conditions:
- What are some behavioural things you do to regulate temperature ?
- metabolism is ramped up
- eat
- drink warm drinks
- shiver
- when we are hot we move water to the outside via sweating
Energy transfer among objects? (3)
- Conduction - energy transfers throughout the body…
- Convection -gaining heat from the environment
- Radiation - gain heat from environment
L> animals typically generate more metabolic heat than plants do …mobility provides a mode for us to keep within our desired range
**bounce the radiation back i.e. losing heat
Energy Exchange within Environment :
-Animals are often isolated from the surrounding environment via?
boundary layer
Energy Exchange within Environment :
- layers of insulation change the body’s?
- conductivity
* *temperature differential been the outside and indie
Types of Temperature Regulation?
- Homeotherms
- Poikiloththerms
- heterotherms
Types of Temperature Regulation:
-Homeotherms ??
maintain constant internal temperatures independent of external temperatures by endothermy (internal heat production…..physiological generation and regulation of body temperature by metabolic means : the property or state of being warm-blooded)
Types of Temperature Regulation:
-Poikilotherms??
- maintain body temperature through external sources: ectothermy (An organism that regulates its body temperature largely by exchanging heat with its surroundings; a poikilotherm)
- *ex: snakes..absorbing heat…their body temp is the same as the environment
Types of Temperature Regulation:
- Heterotherms?
- use both endothermy and ectothermy depending on conditions
Ex: bears going into hibernation
Poikilotherms are affected by environment:
Environmental temperatures control the rates of?(2)
- metabolism and activity
Poikilotherms are affected by environment:
- they gain and lose ___ easily from environment
heat
Poikilotherms are affected by environment:
- explain the graph
y= body temperature (C)
x= ambient temperature
- linear! both are increasing together and would decrease together
Poikilotherms are affected by environment:
- explain graph
y= metabolic rate (arbitrary units)
x= body temperature
- exponential increase
- as body temperature goes up so does metabolism
Poikilotherms are affected by environment:
- why is being a poikilotherm a bed adaptation for large organisms?
- poor strategy because the whole body cannot change at the same rate…its easier for a small body with a larger surface:volume ratio
Operative temperature:
- of a snake…describe graph
x= hour of day
y= temperature (C)
- temp variations in about 4/5 degrees
- amphibians can change by about 10
- only active within the operative range (dotted line)
- higher movement is around lunch - 9pm(cold temps (below zero)
- higher activity during 9am-3pm…(temp at about 15C)
- higher activity during 8am-1
- *as temp increases the hour of operation range becomes narrower
Some animals change position to regulate temperature aka
microhabitats
Example of changing microhabitats to regulate temperature ?
- snake
17C its under a tree for shade… - 18C its in the water
- 30C its laying on a rock
- then it shelters itself under a rock (temp brought down to 14)
- goes underground (temp of 16)
**in morning it sits and collects heat…then it begins moving around and getting active…if it gets too hot they stop…hide or lay on a rock so they do not lose a lot of heat /gain too much
Water species and temp regulation?
- normally they are the exact same temp of the water
- fish are very poorly insulated
- not trying to maintain heat but stay constant with the environment
- *heat produced in the muscles moves to the blood –>gills—>disperse to the environment
Aquatic environments generally show less/more temperature variation compared to terrestrial environments
less
Homeotherms:
- maintain body temp by?
- expending energy…
- minimize thermal constraints within environment
Homeotherms:
- thermal neutral zone?
- where you want to keep your body temp (stable temp)
- *at either extreme ends (cold or hot) the body will increase or slow metabolism depending on their need …
- *really cold temp=high resting metabolic rate
- *hot temp= lowish resting metabolic rate
Homeotherms:
- perks?
- high level of energy production (aerobic respiration)
- can sustain physical activity
- exploit a wider range of thermal environments
- insulation
What are some of the things that allow Emperor Penguins to maintain their body temperature in winter?
- huddle together sharing body heat! …they move around within the huddle (endothermy )
- hold eggs at their feet and cover them with a piece of skin that hangs down
- a lot of resources within their body to help them maintain metabolic heat
Homeotherms ??
An organism, such as a mammal or bird, having a body temperature that is constant and largely independent of the temperature of its surroundings; an endotherm.
Homeotherms are not constrained by?
environmental temperatures
Homeotherms are not constrained by environmental temperatures BUT ??
- must use energy to generate heat, most lost to the environment. Results in disadvantage to being a small homeotherm…
Why would it be bad to be a small animal and a homeotherm?
- very high surface area to volume ratio so it would be very easy to lose heat to the environment…therefore they would require more energy to use to generate heat
Homeotherms:
- explain graph
-x=body mass (kg)
y=mass specific oxygen consumption (litre O2/kg/hr)
as body mass increases the mass specific oxygen consumption reduces as well….therefore less energy is required to heat them up since their ratio of volume to surface area is smaller i.e. its harder/takes longer to lose heat to the environment.
**oxygen consumption + metabolism is directly related to heat
Poikilotherms can allocate more food energy to what?
growth
**do not need to maintain heat…not using metabolism to create heat….
Poikilotherms survive well when?
food and water are limited..
**not using metabolism to create heat therefore they require fewer calories per day and can put energy toward reproduction etc and CAN live in harsher conditions
Are Poikilotherms limited by a min size?
NO
but they are limited by a max size… large= hard to get heat in body from environment
Heterotherms exhibit some characteristics of both ?
homeothermy and poikilothermy
** can generate their own heat but do to have to always gain heat via metabolism…can also from the environment
Heterotherms maintain thermal balance at lower/higher metabolic cost? Ex?
- lower
ex: flying insects..muscles need to be between 30 and 44C to fly efficiently…warm in sun or by shivering flight muscles
Some normally homeothermic animals are ___ under certain conditions.
exothermic
Torpor?
a state of decreased physiological activity in an animal, usually by a reduced body temperature and metabolic rate. Torpor enables animals to survive periods of reduced food availability
Daily Torpor:
ex of animals that do it?
- some mice, hummingbirds
* *reduced metabolic activity during low activity times…(heat matches environment )
Torpor:
- Some ____ and a few ____ mammals go into a long seasonal hibernation
- poikilotherms
- heterothermic
Torpor:
- hibernation?
a state of inactivity and metabolic depression in endotherms. Hibernation refers to a season of heterothermy that is characterized by low body temperature, slow breathing and heart rate, and low metabolic rate.
Torpor:
-some animals draw on stored?
energy reserves
Torpor:
- those that don’t draw on stored energy reserves do what?
- most rouse periodically and drop back into torpor
- *when coming out of this they can quickly generate heat so when they wake up they can be active right away again
- *large surface area to volume ration in smaller animals…= only occurs in small animals
Torpor:
- hibernation is for larger/smaller animals
- larger
Torpor:
- hibernating animals
L> describe what goes on with them during hibernation
- energy costs drop dramatically
L> heart rate, respiration and metabolism drop - 10C = temp of body it can go down to
-blood and CO2 levels increase - acidosis
L>lowers threshold for shivering !
**most come up and get rid of body wastes , rehydrate and warm up if their body temp gets too cold -periodically !
evaporative heat loss
What does a graph look like for a homeotherm with its axis:
x= air temp C
y= body temp (c)
- wave like ~ <- like that but much less extreme
body temp increases with air temp a little then it plateaus but once it gets very extreme body temp begins to increase
Cooling:
- many birds and mammals use ____ to lose excess heat.
evaporative cooling
Cooling:
- some animals store heat in their body during the day and do what during the night?
- dissipate it at night
- reducing the need for evaporative cooling
ex: camel- hypothermia
Explain how camels in the desert get cool and the desert conditions.
- snow= only source of water
L>10L a day - clouds provide some moisture but most of it is taken up by the nearby mountains
-Coping: - increase water in take to keep metabolic rate up
-** physiological changes for temp extremes (controlled hypothermia)
Supercooling:
- who does it?
some temperate and arctic species can super cool (freezing point depression)
- *allows them to survive in lsub freezing areas
- lowers freezing point of cells
Supercooling:
- what stops ice crystals from forming in the blood and destroying cells?
Ex: of who does this
- antifreeze proteins in the blood to lower the freezing point of water
- arctic marine fish and wood frogs
Supercooling:
- Wood frog?
- allow themselves to freeze and thaw out in the summer
- as soon as ice touches them they freeze
- they pull the water away from the centre of their body
- flatline , no brain activity, no respiration etc
- blood sugar is distributed throughout the body like an antifreeze
- inside warms up first before its outer ! usually occurring once mating season starts
- **poikilotherms
Countercurrent Exchange System:
- cold environments?
- warm environments?
- veins surround arteries carrying warm blood from heart
- blood bypasses heat exchangers. Venus blood returns near skin surface
Countercurrent Exchange System:
- common in?
- legs of mammals and birds, tails of rodents and also found in tuna
Countercurrent Exchange System:
-Birds have it in their feet…explain
- they let their feet go almost freezing
- heat in blood from heart can diffuse to blood going back to the heart cooling the feet down..
- *also warm blood is going back to the heart.
- keeps blood at a stable temperature?
Countercurrent Exchange System:
- seen also in?
- desert gazelle
- *arterial blood passes in small arteries through a pool of venous blood that is cooled by evaporation as it drains from the nasal region and into the pool…
What about Plants and regulation of temp??
-heat gain by metabolism
-heat loss by radiation
-heat loss by evaporation of water form leaves
-heat loss or gain by convection (wind changing orientation of leaves etc)
- heat gain by radiation
-
Plant microhabitats?(explain how they lower temp when its too hot)
- temp is really high?: soil surface in full sun heats to high temp
- shading of soil surface by low shrubs lowers maximum temp
- lauer of leaf litter lowers maximum temperatures even more
- greater leaf area and numbers twigs of tall shrubs intercept more light, creating the coolest temperature
When a plant is in high temperatures (hot hotty hot) what can they do to cool off?
- desert plants also reduce radiation heat by orienting their leaves parallel to sun so they do not gain a lot of heat..
- open growth form and small leaves increase exposure of plant surfaces to wind
- low conductive heat gain from ground
- high convective heat loss to wind
- highly reflective leaves reduce heat gain by radiation
What can be done when plants are too cold?
- darkly pigmented leaves reduce reflection and increase heat gain by radiation
- compact, hemispherical growth form decreases exposure of plant surfaces to wind
- low convection heat loss to wind
- arctic and alpine plants also increase Hf by orientating their leaves perpendicular to the sun
- ground hugging growth form increases heat gain from solar heated surroundings through radiation and conduction
Animals: Maintaining Water Balance:
- use what?
- excretory system …varies from simple to complex
Animals: Maintaining Water Balance:
- on land they can
gain water and solutes through drinking, eating and respiration
Animals: Maintaining Water Balance:
- how do they lose water?
- through feces, urine, evaporation and exhalation
Temperature managing :
Animals vs plant
Animal:
- lose water by evaporation
- gain water by drinking and eating
Plant:
- plants lose druids by secretions (nectar)
- plants going water from moist part
- plants lose water via evaporation
- plants gain water from the soil and their roots
Animals and Arid Environment
L> what does arid mean?
low in water
Animals and Arid Environment
Adaptation?
- Behavioural?
- relocate, migrate or be active at night
Animals and Arid Environment
Adaptation?
- physiological?
- reduce loss through respiration, lower internal heat production,, concentrated urine and dry feces or capable of dealing with dehydration
Aquatic Species:
- constant exchange of what with the aquatic environment?
- water
Aquatic Species:
- osmosis?
- difference in salt concentration between animal and environment: animal gains( freshwater) or loses (saltwater ) water through osmosis.
Aquatic Species:
- Marine osmoregulation ?
- diffusion
- body fluids less salty than water
- osmotic water loss
- drinks seawater
- salt excretion by gills
- low urine production by kidneys
Aquatic Species:
- Freshwater and osmoregulation?
- osmoregulation
- body fluids more salty than water
- does not drink water
- salt absorbed by cells
- high urine production by kidneys
- osmotic water gain
Some marine organisms are isotonic with seawater. Do freshwater fish have this option?
- fresh water species do not have the option of being isotonic
Daily and Seasonal Rhythms:
- Daily and seasonal light cycles influence ?
activities
Daily and Seasonal Rhythms:
- internal biological clock: controls?
- periodicity , influences hormones
Daily and Seasonal Rhythms:
- Circadian rhythm ?
- daily rhythm
- physiological response to diurnal cycle (when sun is up and down)
- *mechanisms are triggered via light exposure on different portions of our body
Circadian Rhythm:
- mechanism
L> Photoreceptors?
- base of legs in insects, optic nerve in mammals , pineal gland in other certs
- *mammals produce melatonin (hormone), the amount varies with time of day. Measure of chaining day length
- *senses light
- *melatonin = high conc in the dark
- *variations = how we adapt to seasons etc
Circadian Rhythm:
- mechanism
L> Photoreceptors?
L> adaptive value of this?
- prepare for periodic change in environment ..
- activities that are specific to different seasons can be triggered via light keels…
L> migration
L> reproduction
Seasonal Responses:
- In the middle and upper latitudes, activities change with ?
- length of daylight period
- *time of day the sun is setting
- flying squirrel activity…more active at night ..it starts earlier in the winter when it gets darker earlier ..
What sort of seasonal activities of organisms are likely to be affected by changes in day length?
- migration
- reproduction
- foraging
- storing food
- hibernation periods
- how long the light period and dark periods are during those days
Activity cycles in intertidal animals:
- Dominant environmental factor in intertidal?
- *think fiddler crabs
- fiddler crabs active during low tide in burrows at high tide
- in the lab they maintain cycle of activity for a few days
- activity is synchronized by solar (body colour and lunar (tidal activity) clocks
- *sometimes it is so ingrained even if you change light periods they will not change in their behaviour
- via controlling no outside stimulus telling them when the tides are etc
- since they maintain it…there is something going on physiologically telling them low tides are coming
